Drugs for preventing retinopathy in diabetes

Currently, there are no specific preventive drugs for diabetic retinopathy (hereinafter referred to as diabetic retinopathy). The clinically used drugs essentially reduce the risk of occurrence and progression of diabetic retinopathy by controlling high-risk factors and improving fundus microcirculation.

Last week at the outpatient clinic, I met Uncle Zhang, who has been suffering from type 2 diabetes for 7 years. As soon as he sat down, he took out the list of "Special Preventive Medicines for Diabetes Network" searched on his mobile phone. He said that there were people with diabetes around him who had blurred vision. He was afraid that he would follow in the same footsteps and wanted to take medicine in advance to "protect his eyes." I encounter this situation almost three or four times a week. Many people think that they need to find medicines specifically designed to "protect the eyes" to feel at ease. Instead, they ignore the most basic preventive measures - the anti-diabetic, anti-hypertensive, and lipid-lowering medicines you take every day are actually the core medicines of the anti-diabetes network.

After all, the essence of diabetic retinopathy is a disease caused by long-term high blood sugar, high blood pressure, and hyperlipidemia that damages the capillaries of the eye. As long as these three indicators are kept within the standard range, the risk of diabetic retinopathy can be reduced by more than 70%. Let me also mention the previous academic controversy by the way: In the past few years, it was reported on the Internet that metformin can directly protect the fundus of the eyes, and it is also said that thiazolidinedione antidiabetic drugs will aggravate diabetic retinopathy. The 2022 "China Clinical Diagnosis and Treatment Guidelines for Diabetic Retinopathy" has made a clear conclusion: The impact of antidiabetic drugs themselves on diabetic retinopathy mainly comes from the effect of blood sugar control, except for some patients who use pancreatic retinopathy In the early stage of insulin therapy, fundus microaneurysm may temporarily worsen due to rapid drop in blood sugar. As long as follow-up observation is required, there is no need to change dressings. Regarding the controversy over thiazolidinediones, the latest large-sample study also confirmed that as long as there are no contraindications to severe heart failure or edema, it is neutral to the progression of diabetes, and there is no need to adjust the hypoglycemic plan specifically to "prevent diabetes".

If you have been suffering from diabetes for more than 5 years, or if sporadic microaneurysms have appeared in your last fundus examination, but they have not yet reached the level of requiring laser or drug injection, your doctor may prescribe calcium dobesilate for you. This drug is currently the most evidence-based auxiliary drug. Its main function is to improve the permeability of fundus capillaries and reduce leakage. Studies have shown that taking it early can delay the progression of diabetic retinopathy by about 30%. But not everyone needs to take it. I still remember the last time I persuaded a 28-year-old man who was newly diagnosed with diabetes. The young man’s blood sugar was well controlled and his eyes were clean. He insisted on prescribing two boxes of calcium dobesilate for “prevention.”

There are also many patients who ask whether they can take drugs such as Dufaming and Compound Xueshuantong. In fact, the views of Chinese and Western medicine are somewhat different in this regard. The level of evidence-based evidence for this type of medicine in Western medicine is not high, and there is no clear large-scale study that has proven that it can directly prevent diabetes mellitus. However, the traditional Chinese medicine school believes that this type of medicine that activates blood circulation and unblocks meridians can indeed improve the blood supply to the fundus and relieve the symptoms of dry eyes and blurred vision for people with diabetes who have blood stasis syndrome. However, a special reminder is not to buy these types of proprietary Chinese medicines on your own. If you have gastric ulcers, or have recently had bleeding gums or black stools, taking blood-activating medicines indiscriminately may lead to the risk of bleeding. You must first consult a regular Chinese medicine doctor to make a decision.

Oh, by the way, there are still many people who take methylcobalamin and lutein as preventive drugs for diabetes, so I have to mention it here. Methylcobalamin nourishes the peripheral nerves. It is only useful if you have peripheral neuropathy or the optic nerve is damaged. There is currently no evidence-based evidence to support the prevention of diabetes by taking it daily. Lutein has a certain protective effect on the macula, but it cannot prevent diabetes. Don’t be fooled by the merchants’ “eye protection medicine” propaganda. Some patients have asked whether they can take anti-VEGF drugs in advance to prevent diabetic retinopathy. It is completely unnecessary. This drug is used to treat macular edema and neovascularization caused by diabetic retinopathy. Preventive injections are not only useless, but may also increase the risk of intraocular infection, which is not worth the gain.

I have been doing clinical ophthalmology for almost 10 years. Among the patients I have seen with diabetes, 80% have either their blood sugar fluctuates all year round or they do not check their fundus every three to five years. On the contrary, those with diabetes who have their fundus checked on time every year and whose blood sugar, blood pressure and blood lipids are controlled within the standard range, have not had diabetes for 20 or 30 years. To be honest, if there is any "miraculous medicine to prevent diabetes", it would be to stabilize blood sugar, control blood pressure, and check the fundus once a year. If these three things are done well, it will be more effective than spending tens of thousands of dollars on various "eye protection medicines".